Selecting the landing site for 2018 ExoMars Rover

This post was contributed by Birkbeck student, Anja Lanin. Anja attended Dr Peter Grindrod’s lecture, ‘Selecting the landing site for 2018 ExoMars Rover’ during Birkbeck Science Week 2016.

Mars and a rover

Over the last two years, specialist teams in Europe have been working on helping ESA select the landing site for the first European rover on Mars. This is not just a project for PhD-holders, even individual research findings from undergraduate students contribute to the realisation of this mission. Birkbeck students and staff, including the presenter of this talk, Dr Peter Grindrod, have been closely involved. In his talk ‘Selecting the landing site for the ESA 2018 ExoMars rover’, Dr. Grindrod not only brought to light the difficulties in finding an appropriate site in unexplored regions of Mars but also emphasised the problem of balancing safety, and scientific output.

Birkbeck on Mars!

Birkbeck scientists have been directly involved in developing the PanCam stereo-camera system, which is part of the ExoMars instrument payload, led by UCL’s Mullard Space Science Laboratory. This camera will be crucial for understanding the context of rocks and samples investigated by ExoMars.

Risky goals

The ‘search for signs of past and present life on Mars’ is the main goal of this mission, according to Dr Grindrod. The one billion Euro investment will initially rest on the Russian Proton rocket, with an 89% success rate, on the scheduled May 2018 launch date. The precious 300kg solar-powered rover payload is to land on Mars about 7 months later, via parachute and retro-rockets.

Dr Peter Grindrod

Dr Peter Grindrod

Looking for life, but where?

We learn from Dr Grindrod that the rover needs to land on some of the oldest Martian rocks (>3.6 billion years). Why? Geochemical analysis using orbital-based technology indicates that rocks in some of these oldest regions are sedimentary and characterised by hydrated (clay) minerals.

We know that on Earth clay minerals form from the interaction of rocks with water that is neutral in pH and suits terrestrial life. Some of the geologically younger rocks on Mars contain sulfate minerals formed under water-poor conditions and around life-unsuitable acidic water. So we need a site, as Dr Grindrod says, that at one point had some life-friendly water flowing through it depositing soft sedimentary rocks that the rover can get to and drill into.

Access forbidden – the contamination problem

According to Dr Grindrod, the rover is prohibited from landing in what are called ‘Mars Special Regions,’ areas where any terrestrial organisms unintentionally carried by the rover may survive. Thus areas potentially containing terrestrial life-supporting liquid water at present are a no-go. So scientists have been looking for a rover touch-down location in areas where there may have been life in the past but probably not at present.

Zooming in on a landing target

Mars isn’t small, but temperature constraints rule out areas near the cold poles and the seasonally warm southern hemisphere. Equally very hilly areas are also rover unsuitable due to the steep slopes. Keeping these constraints in mind, the most promising geological outcrops scientists were left with covered just 2% of Mars’ surface area. Finally, they had to consider that the rover could land anywhere within a still considerably large ca. 104 x 19 km elliptical area, rather than a particular spot.

Watch Dr Grindrod’s lecture

The chosen few

Two of the eight landing site proposals submitted throughout Europe came from the UK and both made it into the final four.

In the end a site called Oxia Planum was chosen as the destination for the 2018 launch. The location appears to be near the end of an ancient delta-like river drainage network and there may even be different layers present containing different types of clay minerals, possibly suggesting groundwater interaction. However, one problem with this landing site is that some of the surface is covered in small wind ripples – could the small 20 cm ExoMars rover wheels get stuck here??

For the back-up launch date in 2020 two back-up sites have been selected, Mawrth Vallis and Aram Dorsum. The latter location would place the rover near deposits of one of the oldest river systems (now inverted) on Mars and any landing spot would be conveniently located no more than 100 m from a relevant deposit.

Mars, the red planetWhat’s next?

If Oxia Planum for some reason is proved to be not to be safe enough more work is needed to decide which of the back-up sites is best for the alternative 2020 launch. In the end this decision will be up to ESA and the Russian Space Agency.

Let’s remember though, as pointed out by Dr Grindrod, once the rover touches down the scientific results are for us, for every scientist involved, for everyone whose money has contributed to the mission, not just the investors but also the public.

 

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Astrobiology: The search for life on Mars and beyond

This post was contributed by Guy Collender from Birkbeck’s External Relations Department.

There might be life on planets other than Earth, but it hasn’t been discovered yet and Birkbeck scientists are playing their part in the search.

This quest, the awe-inspiring enormity of the universe and the Earth’s 4.5 billion-year history were all discussed at a fascinating lecture as part of Science Week.

The talk on Tuesday 27 March was delivered by Dr Ian Crawford, of the Department of Earth and Planetary Sciences, at Birkbeck.

He mentioned how Birkbeck’s expertise is contributing towards the European Space Agency’s mission to land a spacecraft on Mars and drill below its surface. Dr Claire Cousins is involved through her work at the UCL/Birkbeck Centre for Planetary Sciences in the scientific development of the camera for the ExoMars rover.  

Dr Claire Cousins, of UCL/Birkbeck Centre for Planetary Sciences, carrying out experiments in the Arctic. Photo credit: Kjell Ove Storvik

Dr Claire Cousins, of UCL/Birkbeck Centre for Planetary Sciences, carrying out experiments in the Arctic. Photo credit: Kjell Ove Storvik

Crawford began by explaining his life-long interest in astrobiology – the science of trying to find life elsewhere in the universe based on the history of life on Earth. He said: “The Earth, as far as we know, is the only inhabited planet in the universe. What we know about life on Earth must inform our search.”

Life on Earth
A timeline was set out to show the history of the Earth and the slow evolutionary development of life upon our planet.

Following the birth of the Earth 4.5 billion years ago, its surface was bombarded by giant meteorites and its oceans were vapourised for the first few million years. This was followed by the emergence of a warm, wet and rocky planet – all necessary conditions for supporting life.

As a result, micro-organisms were born about 4 billion years ago. The transition from such origins of life to complex lifeforms took many millions of years, with multi-celled animals similar to “jellyfish” only appearing 600 million years ago.

Today there are thousands of planets across the universe that resemble the Earth as it was when it began to support life 4 billion years ago. This fact led Crawford to predict that microbial life might be common elsewhere in the universe, but multi-celled animals and intelligent life might be rare.

Searching for life on Mars
The history of Mars exploration followed, including details about the six spacecraft that have landed on the red planet. The dried-up river valleys on Mars indicate that rivers did exist in earlier times, leading Crawford to suggest that it was an “inhabitable” planet in the past.

He said: “There is no doubt that Mars was a warm, wet and rocky place, exactly the kind of place that life should have evolved upon.” Today’s Mars is inhospitable due to its the cold temperatures (-60 degrees), no ozone layer, and its red, dusty surface.

Despite finding nothing so far, the search for whether Mars supports life now, or ever did in the past, continues. The Mars Science Laboratory robot is due to land on the red planet this August, and the plan is for the ExoMars rover to follow suit in 2018.

Future space exploration
Crawford added that there will be no definitive answers about current or past life on Mars until field geologists step foot on the planet, and this remains years away. In response to a question, Crawford said that sending humans to Mars might, technologically, be possible by 2030 (more likely by 2060), but this would be unlikely because of economic and political considerations.

He also spoke about the need for better telescopes, and other potentially inhabitable parts of the solar system, including Europa – one of Jupiter’s moons – and Enceladus – one of Saturn’s moons.

Extraterrestrial intelligence
The question of aliens was also addressed, with Crawford saying that it is unlikely that extraterrestrial intelligence will be discovered, especially as nothing has been discovered since the search began 50 years ago. Whereas finding multi-celled animals elsewhere in the universe might be rare, finding lifeforms capable of sending technology might be even rarer. He said: “I think the galaxy looks like a quiet place.”

Despite finding nothing so far, Crawford stressed the importance of continuing to search for life in the universe.

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